A numbering system using a base number of 16 and including the ten decimal digits (0 to 9) along with six alpha digits (A to F). Thus. a digit is available to represent each of the possible values of a 4-bit binary digit.

A type of pressure-tube anemometer, named after the inventor.

A colloquial term in western Australia for a squall, associated with thunder, on the northwest coast in summer.

That part of an audio-modulated radiosonde consisting of the baroswitch, the sensing elements, the reference elements, and the relay.

A strong wind characterized by a sudden onset, a duration on the order of minutes, and a rather sudden decrease in speed.

The portion of the strearnflow during any month or year derived from precipitation in previous months or years.

See instrument error, observational error. random error, standard error, systematic error.

The rate of decrease of pressure per unit distance at a fixed time.

A halo phenomenon consisting of a horizontal circle passing through the moon, corresponding to the parhelic circle through the sun. Produced by reflection of moonlight from ice crystals.

An instrument for studying, or examining substances in, polarized light. See Savant polariscope.

A pointed device which indicates the amount of resistance encountered when it is forced into a material such as snow or soil. See ram penetrometer.

Literally "not wet", containing no liquid.

An empirical curve relating stream discharge or stage at a point on a stream to discharge or stage at one or more upstream points and, possibly. to other parameters. Also called stage relation.

Closed, curved, flexible tube of elliptic cross section which is deformed, according to type, by variations of atmosphere spheric pressure or temperature and so provides a measurement of the particular parameter.

Difference between the instantaneous wind velocity at a point and the mean wind velocity taken over a given time interval. Also called fluctuation velocity.

That temperature at which, in a specified latitude, the reading of a particular barometer requires no temperature or latitude correction.

An aneroid barograph designed to record atmospheric pressure variations of very small magnitude.

Binary Coded Decimal. A coding system in which each decimal digit from 0 to 9 is represented by a 4-digit binary number.

An instrument designed to record the duration of sunshine at a given location without regard to intensity. See Campbell- Stokes recorder, Jordan sunshine recorder, Marvin sunshine recorder, Pers sunshine recorder.

Video Display Terminal. An input and display device which includes a keyboard and a screen and allows a human to communicate with a computer.